The present invention relates to a freezer comprising an insulated housing having two opposite walls defining an interior chamber therebetween, the walls respectively defining a charging opening and a discharge opening for respectively charging products to be frozen into the interior chamber and discharging the frozen products from the interior chamber. A stack of hollow horizontal freezer plates through which a refrigerant fluid circulates is arranged in the interior chamber and means for vertically displacing the stack of freezer plates is provided to move the freezer plates successively to the level of the openings. The freezer further comprises means for charging the products to be frozen onto a respective freezer plate through the charging opening at a charging station and for simultaneously discharging the frozen product through the discharge opening. One type of freezer with vertically movable freezer plates has been disclosed in U.S. Pat. No. 3,557,975.
More particularly, this invention relates to freezers of this type wherein the vertical freezer plate displacement means comprises screw jacks. Such screw jacks have the advantage that they permit a precise vertical positioning of the freezer plates but they pose problems with respect to lubrification at the very low temperatures at which they must operate in the freezing chamber.